Immunohistochemical analyses have revealed that basement membrane components, including collagen IV, perlecan, and fibronectin, were increased in the frontal and temporal cortex from subclinical AD (Braak stage III–IV) and AD patients (Braak stage V–VI) compared to controls, whereas no significant difference was detected between subclinical AD and AD cases [130]. This evidence concerns the gene FN1 and Alzheimer disease.